OP talked about improving OSM using StreetComplete. So this is about adding missing speed limits, opening hours, roof shapes, recycling containers, tactile pavement at bus stops, etc. Hardly "creating the map".

When I travel to a place where OSM could need improvement I make sure that at least the hotel I will be staying at, nearby restaurants, bars and museums, etc are correctly tagged with phone numbers, opening hours etc. It is not much work and it gives me an opportunity to decide what I want to do before I leave.

When I get there I then have everything ready offline in OsmAnd. In a way I just update OSM instead of adding my own bookmarks/favorites.